CN102918099A - Composition - Google Patents

Abstract

A composition comprising: (I) 30 to 85 wt% of a polypropylene component comprising a polypropylene copolymer; (II) 5 to 49 wt% of a second component comprising at least one ethylene alkyl (meth)acrylate polymer having a (meth)acrylate content of at least 15 wt%; and (III) 10 to 50 wt% of glass fibres.

Description

combination

technical field

The present invention relates to a new composition for injection molded articles exhibiting excellent scratch resistance while also having desirable mechanical properties. In particular, the present invention relates to a polypropylene copolymer to which at least one ethylene-alkyl (meth)acrylate polymer has been added. It has surprisingly been found that this combination minimizes scratches while maintaining excellent mechanical and tactile properties.

Background technique

Due to its beneficial properties, polypropylene resin is widely used to form a variety of useful materials. Polypropylene resins are well suited for the preparation of flexible structures such as body parts for automotive applications, which include exterior components such as bumpers (bumpers), air dams (air dams) and interior components such as Instrument panels and airbag covers, etc.

Reinforced polypropylene that relies on non-polymeric materials such as metals has previously achieved practical applications in several fields. A specific example of reinforced polypropylene is glass fiber reinforced polypropylene. Such materials allow one to tune the properties of the composition by selecting the type of polypropylene used, the amount of glass fibers and the type of coupling agent.

It is also common practice to use various types of fillers in order to improve or fine-tune the performance distribution (curve, profile) of the polymer. A common filler for polyolefins is talc. This compound is used mainly due to its good cost-benefit ratio, since it can provide acceptable performance at very low cost. However, while talc generally increases the stiffness of the composition, it also has some negative effects on other properties. For example, the addition of talc generally increases the visibility of scratches. Talc is the white color that makes scratches very noticeable.

In general, polypropylene reinforced with glass fibers is particularly prone to scratches. The combination of fiberglass and polypropylene can exacerbate this problem. For injection molded parts, such as automotive parts, it is very important that the part is scratch resistant and that any resulting scratches have low visibility.

Since polypropylenes offer such valuable properties, it is not desirable to discontinue their use, but there is a need to address the problem of scratching and thus improve scratch resistance.

The usual solution today is to use high-density polyethylene (HDPE) additives or slip agents to reduce scuffing (marring). But it is very important that any additives used to reduce minimal scratches or at least visibility do not thereby adversely affect other properties, such as mechanical properties. Additives must also be compatible with other polymers present and other components such as reinforcing glass fibers.

Slip agents such as fatty acid amides currently used in anti-scratch are known to cause odor and fogging problems in the final part and possibly cause stickiness. The addition of HDPE, a typical highly crystalline polymer material, increases haze, which is not preferred in the art.

The present inventors have also found that the incorporation of ethylene-alkyl (meth)acrylate copolymers (EAA) in specific amounts into polypropylene polymers provides excellent scratch resistance to the composition. The discovery that these acrylate polymers can provide polypropylene with excellent scratch resistance is new. It has also been found that this combination of polypropylene and EAA forms a composition which, when molded into desired parts, provides improved tactile properties, in particular parts felt in this composition feel better to the touch than other combined. Finally, the mechanical properties of the composition are maintained. In particular the tensile properties, impact properties, flexural properties of the composition are similar to those of polypropylene alone.

It is therefore contemplated that the use of EAA may allow the elimination of fatty acid amides (ie, slip agents) from these polymer compositions. Typically, these additives are added to improve the scratch resistance of the material, and their positive effect is based on the migration of molecules to their surface which lowers the coefficient of friction. The main disadvantage of these additives is that they increase surface stickiness and also have a negative impact on the taste and odor and fogging properties of the material.

The combination of polypropylene and EAA is not new. US 2007/0066758 describes a combination of anhydride modified polypropylene, conventional polypropylene and EAA. This mixture (blend) is used to bond with glass fibers. The idea is that the combination of anhydride-modified polypropylene and EAA can provide a masterbatch for modified polypropylene resin.

In US 2007/0049682, EAA constitutes the main component of a mixture containing polypropylene. The addition of a scratch improving additive clearly shows that the inventors did not appreciate the value of EAA itself in preventing scratches.

In J Appl Polym Sci, Vol 107, 2500-2508, Gururajan et al. studied the effect of ethylene-methyl acrylate on the properties of blown films formed from polypropylene copolymers.

The inventors have found that the combination of relatively small amounts of EAA with an elastomeric polypropylene polymer produces a mixture with desirable properties for injection molding. This composition is ideally suited for use with reinforcing agents such as glass fibers to provide a composition suitable for use in, for example, automotive part manufacture. The mechanical and tactile properties of the mixture (blend) are excellent.

Contents of the invention

Therefore, viewed from one aspect, the present invention provides a composition comprising:

(I) 30 to 90% by weight, preferably 30 to 85% by weight, of a polypropylene component comprising a polypropylene copolymer;

(II) 5 to 49 wt% of a second component comprising at least one ethylene-alkyl(meth)acrylate polymer having a (meth)acrylate content of at least 15 wt%; and

(III) 0 to 50 wt%, preferably 10 to 50 wt%, glass fibers.

Viewed from another aspect, the invention provides a molded article, in particular an injection molded article, comprising a composition as defined above.

Viewed from another aspect, the present invention provides a process for the preparation of a composition as defined above, comprising: obtaining a first component (I) as defined above, and combining said first component with said The second component (II) and optionally the third component (III) are mixed (blended).

Viewed from another aspect, the invention provides the use of a composition as defined above in injection moulding.

Detailed ways

Ethylene-(meth)acrylate resin (EAA)

The compositions of the present invention comprise at least one ethylene-alkyl (meth)acrylate resin. The term (meth)acrylate is intended to include methacrylates and acrylates, ie compounds of the formula _CH3 - _CH2 =CHCOO- or _CH2 =CHCOO-. Thus, (meth) refers to the optional presence of a methacrylate-forming methyl group. However, the EAA of the present invention is preferably an acrylate.

The term "alkyl" as used refers to C _1-6 alkyl, preferably C _1-4 alkyl. Preferably, EAA may be ethylene-methyl (meth)acrylate, ethylene-ethyl (meth)acrylate or ethylene-butyl (meth)acrylate resins, especially ethylene-methyl acrylate, ethylene-ethyl acrylate or ethylene-butyl acrylate resins (EMA, EEA, EBA, respectively). While mixtures of these resins can be used, it is preferred to use only one EAA. The most preferred EAA is EMA.

The amount of (meth)acrylate (relative to the amount of ethylene) in the EAA resin can vary within wide limits. Preferably an excess of ethylene is present. Typical values for acrylates in EAA polymers are in the range of 15 to 40 wt%, such as 15 to 35 wt%. We have surprisingly found that by using higher levels of EAA in the EAA polymer, eg 20 to 35 wt% acrylate, eg 25 to 35 wt%, an improvement in shrinkage properties can be obtained.

The density of the ethylene-alkyl (meth)acrylate resin may be in the range of 935 to 960 kg/m ³ . Its MFR ₂ /190°C may range from 0.1 to 20 g/10 min.

The amount of ethylene-alkyl (meth)acrylate resin employed in the composition of the invention may be from 5 to 49 wt%, such as from 10 to 45 wt%, preferably from 15 to 45 wt% of the composition. It has surprisingly been found that even at slightly lower EAA contents, eg 5 to 30 wt%, preferably 10 to 25 wt%, excellent scratch resistance can still be obtained without impairing the mechanical properties of the composition.

These EAA polymers are commercially available materials and are available from a number of suppliers, for example under the tradename Elvaloy ^™ .

polypropylene polymer

The polypropylene component of the present invention comprises a polypropylene copolymer. The copolymer preferably has viscoelastic properties.

Preferably the polypropylene component is a heterophasic polypropylene copolymer. Such polymers comprise at least two components, a matrix component and a dispersed phase component (ie, an elastomeric component). Elastomers are amorphous polymers that have a glass transition temperature above them.

The polypropylene copolymer used in the present invention is a commercial product and can be purchased from suppliers such as Borealis. A suitable copolymer is sold under the tradename SD233CF by Borealis.

Preferably at least 35% of the polypropylene component should be present in the composition of the invention. Ideally the polypropylene component forms at least 40wt% of the composition, especially at least 50wt%. The polypropylene composition may be the largest component as a whole composition. There may be up to 90 wt%, such as up to 85 wt%, of a polypropylene component, such as up to 80 wt%, preferably up to 75 wt%, such as up to 70 wt% of a polypropylene component. A preferred range is 35 to 65 wt%. It should be understood that once the amounts of glass fibers and EAA are determined, the amount of the polypropylene component may represent the remainder of the composition (ie make up to 100%). Typically, additives and possibly other components are of course also present, which means that the amount of polypropylene components is correspondingly reduced.

Ideally, the polypropylene component of the present invention comprises a propylene-ethylene copolymer.

In the polypropylene component of the present invention the ethylene content is preferably at least 5 wt%, eg 5 to 30 wt%, preferably 5 to 15 wt%.

The MFR ₂ of the polypropylene component may be in the range of 0.01 to 300 g/10min, preferably 1 to 20 g/10min, especially 5 to 15 g/10min. The polypropylene component typically has a density of about 0.900 g/cm ³ . Density can range from 0.890 to 0.910 g/cm ₃ . The xylene solubility is preferably in the range of 15 to 30, preferably 20 to 25 wt%.

Preferably the polypropylene component is a heterophasic polypropylene copolymer. Such polymers comprise at least two components, a matrix component and a dispersed phase component (ie, an elastomeric component).

Thus, the heterophasic polypropylene used according to the present invention may comprise a matrix phase comprising only one polypropylene polymer component or may comprise more than one polypropylene polymer, such as two, three or four different polypropylene polymers The matrix phase of the components. In a preferred embodiment the matrix phase comprises one polypropylene polymer component or two polypropylene components, preferably one component.

The matrix phase generally comprises at least one polypropylene homopolymer and/or polypropylene copolymer. In one embodiment, the matrix component is formed from polypropylene homopolymer. Alternatively, the matrix component may be formed from a polypropylene copolymer with at least one comonomer, such as ethylene.

Preferably, the matrix phase comprises at least two polypropylene components, preferably (i) polypropylene homopolymer or polypropylene random copolymer in combination with (ii) polypropylene random copolymer.

The polypropylene polymer components for the matrix phase are preferably combined by preparation of the matrix phase, such as in situ reactor mixing (blending), i.e. preparation of the matrix phase in a subsequent polymerization step with a suitable reactor arrangement. different components.

The term "random copolymer" means in the present invention that the comonomer in said copolymer is distributed randomly, ie by statistical intercalation of comonomer units within the copolymer chain. The term "random" copolymer is generally known and used in the art.

The term "comonomer" is defined in the present invention as the type of monomer present in the heterophasic polypropylene composition other than propylene. Preferred comonomers are ethylene and C4-C8 alpha-olefins.

The matrix phase of the heterophasic polypropylene may comprise up to 10 wt% of ethylene and/or at least one C4-C8 alpha-olefin, preferably ethylene, typically 1 to 7 wt%, and in some embodiments 2 to 5 wt%. However, according to the present invention, the matrix phase of the heterophasic polypropylene may also be a homopolymer, wherein the term "homopolymer" also includes embodiments in which small amounts of comonomers of less than 0.1% are present, wherein the comonomers are selected from from those identified above.

The matrix phase of heterophasic polypropylene can be unimodal or multimodal, i.e. the different components of the matrix phase can exhibit similar molecular weight distributions or different molecular weight distributions (also including MFR ₂ values accordingly).

The matrix phase according to the invention preferably exhibits a MFR ₂ (ISO 1133, 2.16 kg load at 230° C.) of 0.5 to 100 g/10 min, such as 2 to 50 g/10 min and in some embodiments 5 to 20 g/10 min.

The matrix phase can form up to 90% by weight of the polypropylene copolymer component.

The bulk _MFR2 (ISO 1133 at 230°C, 2.16 kg load) of the heterogeneous composition is typically 2 to 25 g/10 min, such as 5 to 20 g/10 min and in some embodiments 5 to 15 g/10 min.

Most preferably, the matrix component is a random propylene-ethylene copolymer or a mixture of random propylene-ethylene copolymers.

dispersed phase

The dispersed phase, ie the elastomeric rubber phase, comprises at least one, eg two, suitable elastomeric copolymers. This dispersed phase (rubber phase) can form up to 45% by weight of the total weight of heterophasic polypropylene. A suitable range is between 10 and 40 wt% and in some embodiments 10 to 20 wt%.

The dispersed phase comprises at least one elastomeric copolymer of propylene and one or more olefinic comonomers, preferably ethylene. The rubber phase comprises 5 to 50 wt% of olefinic comonomers, preferably ethylene. The rubber phase preferably comprises a high amount of comonomer, preferably 5 to 40 wt%, more preferably 7 to 35 wt%.

Examples of olefinic comonomers, besides the preferred ethylene, are C4-C8 alpha-olefins. According to a preferred embodiment of the invention, the dispersed phase, ie the ethylene rubber copolymer, is ethylene propylene rubber (EPR). EPR materials are more cost-effective than alpha-olefin rubbers, and they can be synthesized in the final step of a multi-step process, the first step of which synthesizes the base polymer.

In one embodiment, the dispersed phase may comprise at least two elastomeric components, such as described in WO2009/065589.

The most preferred dispersed phase component is a random propylene-ethylene copolymer.

The heterophasic polypropylene copolymers of the present invention can be produced in a multistage process (multistage process) as known in the art. The process may comprise at least one slurry phase reactor and at least one gas phase reactor directly connected in series.

The slurry phase polymerisation may be carried out at a temperature below 75°C, preferably 60-65°C and at a pressure varying between 30-90 bar, preferably 30-70 bar. Preferably the polymerization is carried out under such conditions that 20-90 wt%, preferably 40-80 wt%, of the polymer is polymerized in a slurry reactor or in a plurality of slurry reactors. The residence time can be between 15-120min.

The gas phase polymerization step is carried out by transferring the reaction mixture directly from the slurry phase to the gas phase without removal of unreacted monomers. The pressure is preferably higher than 10 bar. The reaction temperature used is usually 60 to 115°C, preferably 70 to 110°C. The reactor pressure will be above 5 bar, and preferably in the range of 10 to 25 bar, and the residence time will generally be 0.1 to 5 hours. Since unreacted monomer from the slurry phase is transferred into the gas phase, it is important to determine how much unreacted monomer has been transferred to allow for a predetermined determination of how much additional monomer is added to the gas phase. Such measurements can be achieved by simple gas chromatography which allows maintaining the proper monomer concentration.

When vaporized in the gas phase reactor, the liquid medium from the first stage reactor can function as a cooling medium for the fluid bed in the gas phase reactor.

Polymerization is accomplished using any standard olefin polymerization catalyst known to those skilled in the art. Preferred catalyst systems include conventional stereoselective Ziegler-Natta catalysts, metallocene catalysts and other organometallic or coordination catalysts. A particularly preferred catalytic system is a high-yield Ziegler-Natta catalyst with a catalyst component, a cocatalyst component, optionally an external donor (donor). Thus, the catalyst system may comprise a titanium compound and an electron donor (electron donating) compound supported by activated magnesium dichloride, a trialkylaluminum compound and an electron donor compound as an activator.

Heterophasic polypropylene copolymers are well known commercial products and are available from commercial suppliers. Methods for their manufacture are well known.

glass fiber

The composition according to the invention may also comprise glass fibers in an amount of 0 to 50 wt%, preferably 10 to 50-wt%, preferably 10 to 40 wt%, for example 15 to 35 wt%. The glass fibers can be chosen from chopped glass fibers or long (continuous) glass fibers, but typically glass fibers have a length of a few millimeters before compounding (compounding) with polypropylene, such as 3 to 15 mm above, preferably 3.5 to 5 mm of chopped fibers. Glass fibers of this type are commercially available and examples thereof are P968 by OCV, T480 by NEG, Thermoflow 738 sold by Johns Manville or others.

Typically glass fibers have a diameter of about 10 to 15 μm, although other glass fiber diameters are also contemplated in accordance with the present invention.

Coupling agents for improving the coupling of the glass fibers in the polymer matrix may also be included in the composition according to the invention. Any type of coupling agent may be used and illustrative examples thereof are maleic anhydride grafted propylene homopolymers or propylene-ethylene block copolymers, as well as Chemtura's Polybond 3150/3200, Eastman's Epolene G3003 and Exxon's Exxelor PO1015 or PO1020. The amount of coupling agent depends on the type and amount of glass fibers, but generally the coupling agent is added in an amount of 0.5 to 5 wt%, based on the weight of the composition.

In a highly preferred embodiment, no coupling agent is used.

Additional components

The composition may also contain additional polyolefin components to enhance the properties of the composition. For example, consider adding HDPE, LDPE or LLDPE. Furthermore, the optional addition of additional elastomeric polymers is contemplated.

Accordingly, the composition of the invention may comprise HDPE, in particular HDPE having a density of at least 940 kg/m ³ , such as 940 to 980 kg/m ³ . Such polymers are preferably ethylene homopolymers. Alternatively there may be LLDPE or LDPE eg having a density between 905-935 kg/m ³ . Such polymers may be present in amounts up to 15% by weight of the composition, such as up to 10% by weight.

Additional elastomeric components such as ethylene copolymers, including ethylene-propylene copolymers and also preferably higher alpha-olefins having 6 to 12 carbon atoms, may also be added. A particularly preferred option is the inclusion of ethylene-1-octene copolymers with a high ethylene content, preferably above 80-mol%. These copolymers may be added in amounts of up to 15% by weight, preferably up to 10% by weight, based on the total weight of the composition. Commercially available examples of preferred ethylene copolymers are polymers sold under the tradename ENGAGE by DuPont Dow, for example ENGAGE 8100, ENGAGE 8180, ENGAGE 8200 and ENGAGE 8400.

Examples of ethylene-propylene elastomers that can be used are elastomers used as polyolefin modifiers, such as those sold by Polimeri under the trade name DUTRAL, i.e. having an MFR (230°C/5kg) of 1 to 5 g/10min Ethylene-propylene elastomer.

The compositions of the present invention may further comprise conventional additives such as antioxidants, stabilizers, acid scavengers, clarifiers, colorants, anti-UV agents, nucleating agents, antistatic agents and mold release agents. Typically, these additives may be present in amounts of less than 2 wt%, more preferably less than 1 wt%, each relative to the total weight of the composition.

It is particularly preferred that fillers, such as talc or nanofillers, are present in the compositions of the invention. Fillers may be present in the compositions of the invention up to 15% by weight. The amount of filler present may range from 5 to 12 wt%. Ideally, the filler is talc. Preferably no fillers are added.

Composition properties

The total composition (total ingredients) of the invention (with any optional glass fibers present) may have a MFR _2/230 of 1 to 10 g/10 min.

The modulus of elasticity of the composition may be at least 900 MPa, preferably at least 1500 MPa.

The tensile strength is preferably at least 12 MPa, especially at least 25 MPa.

Charpy notched impact strength values are also higher. The Charpy notched impact strength value at 23° C. is preferably at least 20 kJ/m ² , in particular at least 35 kJ/m ² .

Low temperature Charpy notched impact strength (-20°C) of at least 7 kJ/m ² .

The compositions of the invention also exhibit very high scratch resistance. Scratch resistance was measured on injection molded test specimens of the compositions described in detail below.

Parts made from the polypropylene resins of the present invention have high scratch resistance. When parts are scratched, especially those containing white fillers such as talc, obvious scratch marks can be seen on the part. ΔL is a measure of the change in luminance (determined using a spectrophotometer), and thus represents a measure of the noticeability of the scratch. High ΔL values indicate highly visible scratches. Usually scratches appear as white marks on black surfaces. Ideally, however, scratches on the surface should be invisible. The lower the ΔL value, the less visible the scratch is, and therefore the darker the scratch. A negative ΔL value indicates the presence of a scratch that is substantially invisible to the eye. The measurement of ΔL was performed using a colorimetric method.

The ΔL values obtained in the present invention are preferably less than 0.7, in particular less than 0.5. In some embodiments ΔL values can be as low as 0.25 or less. In a very preferred embodiment, the ΔL value is zero or negative.

The measured ΔL is the untreated resin surface and the steel ball tip with a diameter of 1mm, the cutting force of 10N and the cutting speed of 1000mm/min are used to cut the cross hatch on the resin surface with a distance of 2mm for each grid line. difference in brightness between resin surfaces. Full details of the testing procedures are provided in the Examples below.

The compositions of the invention also have an excellent touch and feel as we measure according to Shore D hardness. A composition with a lower Shore D value indicates that the composition has a softer touch and thus a more velvet or silk like feel. This is important for a variety of applications, such as interior automotive components where look and feel are critical in sales vehicles. The Shore D value may be less than 50, preferably less than at least (minimum) 45.

The polypropylene composition of the present invention is particularly useful in the production of molded and/or extruded articles by employing conventional injection molding techniques, blow molding techniques and/or extrusion techniques.

Preferably, these articles are exterior parts or interior parts of body parts for automotive applications. External components can be shock absorber (bumper) cover, external waistline (fascia), air dam (air dam, air dam) and other trim (trim), internal components can be instrument panel, airbag cover, etc. .

The invention will now be described with reference to the following non-limiting examples.

Description of measurement method

Melt Flow Rate (MFR ₂ )

The melt flow rate is determined according to ISO 1133 at 230°C (for PP or PP-copolymer) and 190°C (for PE) under a load of 2.16 kg.

density

Density was measured using ISO1183.

Scratch resistance (scratch resistance)

For the measurement of scratch resistance, a Cross Hatch Cutter Model 420p produced by Erichsen was used.

Injection molding sample, 60*60mm, 3mm thickness, material temperature: 240°C, tool temperature: 40°C, back pressure: 600bar

Use fine particles (VW K09-particles) to cut out mesh lines (cross scratches) on the surface of the sample (40×40mm, 2mm spacing for each grid line). The instrument is equipped with a steel ball tip (1.0mm). The cutting force is 10N. A cutting speed of 1000mm/min was used.

Scratch evaluation was carried out by measuring the ΔL value with a spectrophotometer according to DIN 5033 (CIELAB, D65, 10°, 45/0). This measurement corresponds to the difference in brightness between the treated and untreated polymer surface. Changes in brightness are represented by ΔL values. ΔL<1.0 is considered to have high scratch resistance and low scratch visibility, respectively.

Notched Charpy impact strength

The measurement of the notched Charpy impact strength was performed according to ISO 179/1eA at 23°C and -30°C by using injection molded test specimens using molding as described in EN ISO 1873-2.

Flexural modulus (strength/modulus/stress/strain) is determined according to ISO 178 using injection molded test specimens 80x10x4 mm molded as described in EN ISO 1873-2.

Tensile Properties:

Tensile properties (strength/modulus/stress/strain) were determined according to ISO527/1B using injection molded test specimens molded as described in EN ISO 1873-2 (170x10x4mm) according to ISO527.

Shore D

Shore D was determined according to ISO868 on molded test pieces of 4mm thickness. The Shore hardness is determined after the pressure foot has been in firm contact with the test specimen for 15 seconds. Molded test specimens according to EN ISO1873-2.

Example:

The polypropylene used in the examples was SD233CF, a very soft random heterophasic copolymer available from Borealis. It has an ethylene content of 8 wt%, MFR _(230/2.16) of 7 g/10min.

The ethylene methyl acrylate polymer used was an Elvaloy grade available from DuPont. The grades used are Elvaloy1330, 1913 and 1609.

In these grades the acrylate content is given in the last two digits of the grade name (so 30wt% for Elvaloy 1330, 13wt% for Elvaloy 1913, 9wt% for Elvaloy 1609).

The glass fiber used was P986 supplied by OCV.

The composition in Table 1 then also contained standard polymer additives, namely 0.2% Irganox B225, 1% Plasblack 3638 (with 40% carbon black), and 1% Exxelor PO1020, but no talc. To add up to 100%, the amount of additive is deducted from the polypropylene fraction.

In the following examples, compositions were prepared using the components in the table below, using a twin screw extruder with a temperature profile starting at 180°C, and using an extrusion temperature of 220°C. Fiberglass was added via a sidefeeder.

Table 1 provides details of the compositions prepared and their properties.

It can be seen that the use of Elvaloy 1330 (Examples 1 and 2) allows to achieve a negative scratch resistance. In the controls using acrylates with lower acrylate content (Comparative Example 2-Comparative Example 5), the scratch resistance performance was worse than in the absence of acrylate (Comparative Example 1).

It should be noted that the addition of a large amount of acrylate reduces the tensile modulus and flexural modulus and tensile strength. There is also a small decrease in impact strength at room temperature. However, excellent scratch resistance and good mechanical properties are still exhibited by adding 20wt% EAA.

Claims (12)

1. A composition comprising: (I) 30 to 85% by weight of a polypropylene component comprising a polypropylene copolymer; (II) 5 to 49 wt% of a second component comprising at least one ethylene-alkyl(meth)acrylate polymer having a (meth)acrylate content of at least 15 wt%; and (III) 10 to 50 wt% glass fibers. 2. A composition according to any preceding claim, wherein polymer (II) is ethylene-alkyl acrylate. 3. A composition according to any preceding claim, wherein polymer (II) is ethylene-methyl acrylate. 4. A composition according to any preceding claim, wherein the amount of acrylate comonomer in the polymer (II) is in the range of 20 to 35 wt%. 5. A composition according to any preceding claim, wherein polymer (I) is a heterophasic polypropylene polymer. 6. A composition according to any preceding claim comprising 15 to 35 wt% glass fibres. 7. A composition according to any preceding claim, comprising 15 to 35 wt% ethylene-alkyl (meth)acrylate polymer. 8. A composition according to any preceding claim comprising 35 to 65 wt% polypropylene polymer (I). 9. A composition according to any preceding claim, comprising a ΔL value of less than 0.7, especially less than 0.5. 10. A molded article, especially an injection molded article, comprising a composition as claimed in any one of claims 1 to 9. 11. A method for preparing the composition claimed in any one of claims 1-9, comprising: obtaining the first component (I) as defined in claim 1, and said first component Mixed with said second component (II) and said third component (III). 12. Use of the composition as claimed in claims 1-9 in injection moulding.